five more sections to connect to the current rail system. An 8.3 mile (13.4 km) expansion has been approved to run the service from the Uptown through Texas Southern University, ending at the University of Houston campus. In addition, Harris County Transit operates some services in the portion of Clear Lake City in Houston. Airports Airports within the city limits Houston is served by two commercial airports—the largest of which is the George Bush Intercontinental Airport (IAH). The airport is the 11th-busiest in the United States for total passengers, and 16th busiest worldwide. Bush Intercontinental is United Airlines second largest hub, with more than 650 daily departures (more than 450 of which are United flights). Bush Intercontinental currently ranks second in the United States for non-stop domestic and international service (221 destinations), trailing only Atlanta Hartsfield with 250 destinations. In 2006, the United States Department of Transportation named Bush Intercontinental one of the top ten fastest growing airports in the United States. The second-largest commercial airport in Houston is the William P. Hobby Airport (named Houston International Airport until 1967). The airport operates primarily small to medium-haul flights and is the only airport in Houston served by Southwest Airlines. The third-largest airport and former U.S. Air Force base, Ellington Airport (formerly Ellington Field), is primarily used for government and private aircraft. At one point, Continental Express operated flights across the city to Bush Intercontinental primarily for residents of southeast Houston and Galveston County. Passenger flights ended on September 7, 2004. The Federal Aviation Administration and the state of Texas selected the Houston Airport System, which manages Bush, Hobby, and Ellington, as Airport of the Year for 2005, largely because of its multi-year, $3.1 billion airport improvement program for both major airports in Houston. Andrau Airpark, a privately owned airport, was located in Houston until 1998; it was demolished and as of 2008 contains the Royal Oaks Country Club subdivision. Airports for fixed-wing aircraft outside the city limits Publicly owned airports outside the city limits The following publicly owned airports are in the Houston area: Harris County: La Porte Municipal Airport in La Porte Baytown Airport in unincorporated east Harris County, north of Baytown Fort Bend County: Sugar Land Regional Airport in Sugar Land Galveston County: Scholes International Airport at Galveston, a general aviation and military airport, is located in Galveston Montgomery County: Lone Star Executive Airport in Conroe Brazoria County: